S
M
T
W
T
F
S
26
85°
71°
27
88°
75°
28
87°
73°
29
85°
72°
30
75°
64°
1
64°
53°
2
75°
50°
3
79°
48°
4
80°
50°
5
83°
66°
6
83°
67°
7
78°
58°
8
75°
64°
9
87°
69°
10
89°
68°
11
77°
65°
12
77°
62°
13
93°
61°
14
90°
65°
15
87°
66°
16
85°
75°
17
86°
77°
18
87°
75°
19
87°
74°
20
81°
68°
21
80°
69°
22
79°
68°
23
82°
70°
24
83°
71°
25
83°
71°
26
84°
70°
27
87°
69°
28
88°
70°
29
89°
68°
30
86°
71°
31
88°
72°
1
90°
72°
2
89°
71°
3
86°
70°
4
86°
67°
5
87°
71°
6
89°
73°
Temperature Graph
°F
Avg. Hi
Avg. Lo
Actual Hi
Actual Lo
Forecast Hi
Forecast Lo
May Weather in Onalaska
Onalaska's May 2026 forecast shows daily high temperatures ranging from 79° to 90°, with overnight lows between 67° and 77°. The average high for May is 86° with an average low of 71°. AccuWeather's monthly forecast extends further ahead than any other source, with day-by-day RealFeel® Temperatures giving a complete picture of how May weather will actually feel in Onalaska. See also: June | July | August.
